With rapid development of intelligent terminals and mobile applications, mobile data traffic has sharply increased. Consequently, it is more difficult for a current 3rd Generation Partnership Project (3GPP) network to meet increasing requirements for mobile data traffic. Therefore, mobile operators expect to use a non-3GPP network to bear some or all mobile data traffic of the 3GPP network by means of inter-network cooperation between the 3GPP network and the non-3GPP (non-3GPP) network, so as to relieve a burden on the current 3GPP network. For example, when a Long Term Evolution (LTE) network is overloaded, some or all services of some user equipments (UE) within coverage of a wireless local area network (WLAN) are offloaded to the WLAN, so that a service overloaded status of the LTE network can be relieved.
However, after some or all the services of the UE are offloaded to the WLAN, the services cannot be converged at an LTE protocol layer for processing. Therefore, UE service continuity cannot be ensured, and service quality of the UE is deteriorated, thereby affecting user experience.